they are actually in a shopping trolley.
sounds suss but its a good set up . and I can take my girls for walks around the place.
I just have a fan running on them all day.
pretty exposed.
yea need to control the air flow so you only get positive flow into the grow room and no escaping air.. create a small hole for the inlet and attach ducting with a carbon filter.. then have an air blower connected to an exhaust vent via ducting .. with no air escaping the room and only positive flow into the room, there should be no smell (outside the grow room of course)
good luck!